Re: Projecting VM with a TDC 116

[P3D Gabriel Jacob <jacob@xxxxxxxxxxxxxx>]

Gabriel
>>BTW since getting the Dr.TDC 116 ;-) I have been working on a carrier
>>for projecting VM reels with it! Don't know if this is been done before
>>but since I don't have a VM Stereomatic 500, thought it would be nice to
>>simulate one or rather improve on it, since this would be brighter than
>>the single lamp Stereomatic. 

Dr.T
>Just wondering, how much brighter is the image just because two lamps
>are used instead of one?  

Dr.T brought up some good concerns regarding how much brighter the two lamps
would be compared to one. In my enthusiam in thinking that the TDC 116 using
two 500W bulbs would be brighter than one 500W bulb VM Stereomatic I
neglected to take into account the area of the light radiated onto the chip
area. The reason being is that since the TDC 116 was designed for much larger
chips, the focussing of the light is over a broader area. With the VM carrier
used in the TDC this light is wasted because only a portion of the light over
the roughly 8p area is utilized. All things being equal (assuming the same
effiencies in the condenser optics for both projectors) the TDC would use
roughly one quarter of the light energy available in projecting VM reels.
Thus maybe 250W is actually being used compared to 500W for the Stereomatic
or half the output of the Stereomatic! Nevertheless if this is actually the
case I am still very happy with the results and in observing the results
with projecting VM reels with the TDC the brightness was adequate but not
overly bright. 

>Also, how about the 4" and 5" lenses of these projectors?  Here, we consider
>the 3" lenses to be too long for this format. A VM with 3" lenses projects
>at a smaller image than the TDC 116 with 5" lenses from the same distance
>from the screen... 

Yes that is true but wasn't a concern of mine. The only thing I was setting 
out to accomplish was to be able to project VM reels with some sense of
simplicity in having a carrier able to hold, position, and advance the reels.
Brightness was another concern but alas wasn't as bright as I hoped for.
The size was indeed on the small side as you point out. I estimate
(not measured) that at about 20 feet projection distance the image was about
25 inches. On the small side, but heck I was happy to be able to view 25
inches compared to viewing 0 inches if no carrier was available to accomodate
the VM format. 

>Minor details... Good luck with your project! -- George

In that regard, disregarding the minor details above thanks and I think
the project was successful.

Gabriel
 



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